LED Luminaire

ABSTRACT

A lighting device comprises rectification circuitry configured to produce rectified alternating current (AC) from input AC comprising a plurality of cycles. The lighting device further comprises lighting circuitry coupled to the rectification circuitry. The lighting circuitry comprises first, second, and third sets of LEDs. The sets of LEDs are configured to turn on in sequence at least twice per cycle to together develop an output level of at least about 2000 lumens.

RELATED APPLICATIONS

This application is a continuation of prior application Ser. No.15/727,178, filed Oct. 6, 2017, which is a divisional application ofapplication Ser. No. 14/618,819, filed Feb. 10, 2015, now U.S. Pat. No.9,788,378, the entire disclosure of each being hereby incorporated byreference herein.

FIELD OF DISCLOSURE

The present subject matter relates to electrical power circuits, andmore particularly, to a circuit for operating an LED luminaire.

BACKGROUND

LED-based luminaires have become increasingly popular of late due to thedevelopment of high lumen output LEDs that operate at low power. Whilesuch luminaires save energy costs, some of the electrical power suppliedto the LEDs is converted into heat that may require dissipation toprolong the usable lives of the LED devices. Further, heat is typicallydeveloped by other elements, such as one or more driver circuits thatdevelop power of an appropriate magnitude for the LEDs. Inasmuch as theheat developed by the LEDs is directed opposite to the direction thelight is emitted, heat dissipation devices are typically disposed inthermal contact with a circuit board on which the LEDs are mounted. Inother designs the thermal dissipation device may include the circuitboard itself (with or without a heat exchanger in thermal contacttherewith), in which case the circuit board may be made of a thermallyconductive material, such as metal (aluminum, copper, one or morealloys) and/or a metal and composite material and/or a combination ofthermally conductive and non-thermally conductive materials (forexample, an alumina substrate with one or more flex connectors).

Still further, other non-heat producing circuit components may bepackaged on the same circuit board as the LEDs and the drivercircuit(s). The other non-heat producing circuit components includepower connection terminals, one or more surge protection devices, arectification circuit, and the like. Packaging all of the circuitcomponents together results in a modular, all-in-one design thatsimplifies the process of designing the electrical and mechanicalcomponents of the luminaire. The modular design results in someduplication of components when multiple modular packages are used in aluminaire. Further, disposing all of the non-heat producing circuitcomponents on the circuit boards together with the heat producingcircuit components results in a relatively large combined size of heatdissipating circuit board being necessary, again, particularly inluminaires employing multiple modular packages, which contributes tocost.

A luminaire as described above may further require the capability ofoperating on different input voltages, such 120 volts or 240 volts RMS.While circuit designs are known that permit such operation (such as aswitched mode power supply circuit that uses a buck regulator, a boostregulator, a buck-boost regulator, etc.), such designs are complex andrelatively expensive.

SUMMARY

According to one aspect, an outdoor luminaire comprises a housingadapted to be mounted on an outdoor structure, an input disposed in thehousing that receives AC power, and at least one rectification elementcoupled to the input and which produces rectified AC electrical powercomprising a plurality of cycles. At least one LED driver circuit iscoupled to the at least one rectification element and a plurality ofLEDs is coupled to the at least one LED driver circuit. The LEDs areturned on at different points during each of the plurality of cycles andtogether develop an output level of at least about 2000 lumens.

Other aspects and advantages will become apparent upon consideration ofthe following detailed description and the attached drawings whereinlike numerals designate like structures throughout the specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view taken from below of a luminaireincorporating an operating circuit;

FIG. 2 is an exploded isometric view taken from below of a luminaireincorporating an operating circuit;

FIG. 3 is isometric view of two prior LED operating circuits and LEDmodules disposed on two circuit boards;

FIG. 3A is a bottom elevational view of the operating circuits of FIG.3;

FIG. 4 is a fragmentary bottom elevational view of an LED operatingcircuit as disposed in the luminaire of FIG. 2;

FIG. 4A is an isometric view of one of the circuit boards and associatedcomponents of FIG. 4;

FIG. 5 is a schematic diagram of the operating circuit of FIG. 4;

FIG. 5A is a graph of a rectified waveform over time and the resultingdrive on LEDs, according to one or more embodiments of the presentdisclosure.

FIG. 6 is a schematic diagram of a portion of an LED operating circuitincluding an adapter circuit in a first configuration; and

FIG. 6A is a schematic diagram of a portion of an LED operating circuitincluding an adapter circuit in a second configuration.

DETAILED DESCRIPTION

Disclosed herein is luminaire 20 for general lighting such asillumination of an open or large enclosed space, for example, in a ruralsetting, a roadway, a parking lot or structure, or the like. Referringto FIG. 1, the luminaire 20 includes a housing 24 adapted to be mountedon an outdoor structure having a transparent optical member 26. Theluminaire 20 may be mounted on a pole or stanchion 28 and retainedthereon by a clamping apparatus 30. The luminaire 20 may further includean optional reflector 32 and optional plastic or glass optical elementin the form of a transparent shroud 34 secured in any suitable fashionabout the optical member 26.

Referring next to FIGS. 3 and 3A, a first embodiment of a lightgenerating arrangement is shown comprising first and second lightingmodules 40, 42 disposed on inclined side surfaces 44, 46, respectively,of a base 54. The base 54 may be mounted on a mounting surface (notshown) behind the optical member 26. The lighting modules 40, 42 areideally substantially or fully identical, and hence, only the lightingmodule 40 will be described in detail herein. Each lighting module isdescribed and shown in U.S. patent application Ser. No. 62/088,375,entitled “Voltage Configurable Solid State Lighting Apparatuses,Systems, and Related Methods,” filed Dec. 5, 2014, the entire disclosureof which is hereby incorporated by reference herein. The lighting module40 includes a circuit board 44 and an LED enclosure 46 mounted on thecircuit board 44 that houses a number of LEDs, such as forty or adifferent number of separate LED dies and which includes an opticalelement 48 in the form of a yellow phosphor-coated encapsulant and/oranother optical element, such as a lens. If desired, the optical element48 may comprise another optical element that is coated or uncoated. TheLED enclosure 46 is disposed at a central portion 50 of the circuitboard 44 and electrical circuit components are disposed at ends 52, 54of the circuit board 44, although the components may alternatively or inaddition be disposed at other locations of the board 44. The circuitcomponents include electrical connection terminals disposed in aconnector 56, surge protection component(s) 58, fuse(s) 60, resistors62, diodes 64, and a driver circuit 66. Other components may also beincluded as necessary or desirable. The circuit board 44 is made ofalumina or another thermally conductive material with flex, FR4, orother insulating material that allows for simplification of pick andplace and reflow processes.

While the light generating arrangement of FIG. 3 is effective to developlight of sufficient lumen output and desired illumination distribution,it has been found that costs can be reduced by rearranging componentsonto a combination of circuit boards and integrating all of the LED diesinto a single package as seen in FIGS. 2, 4, and 4A. Specifically, ingeneral, non-heat producing components of an LED operating circuit(and/or components that develop little heat) are mounted on a firstcircuit board 70 (FIG. 4) that need not dissipate substantial amounts ofheat. The first circuit board 70 may therefore be made of inexpensivematerials, such as FR-4 (a flame resistant fiberglass reinforced epoxylaminate). The remaining, substantial heat-producing components aremounted on a second circuit board 72 made of one or more materialscapable of substantial heat dissipation. The second board 72 cancomprise any suitable circuit carrier and/or circuit carrying structurenot limited to a ceramic-based substrate, for example, alumina (Al₂O₃),high reflectivity alumina, or any other suitable ceramic orceramic-based material. In other aspects, the second board 72 comprisesmultiple layers of material, where at least one layer is a ceramic or adielectric base layer. The second board 72 can comprise any suitablematerial, such as ceramic, aluminum, a composition including aluminum,such as Alanod (e.g., Al and Ag), etc., and combinations thereof havingone or more layers, such as traces, provided thereon. In some aspects,the second board 72 comprises a printed circuit board (PCB), a metalcore printed circuit board (an MCPCB), a laminate structure having oneor more layers connected via adhesive, a flexible printed circuit board(“flextape” PCB) comprising a polymer-like film having at least oneconductive layer within one or more layers of a flexible plastic resin(e.g., polyimide, Kapton® from DuPont), and one or more adhesive layerscomprising a tape-like adhesive provided on the flextape for easyconnection to a ceramic body.

In some aspects, the second board 72 can comprise a ceramic base havingone or more (e.g., and optionally flexible) layers adhered thereon asdiscussed, for example, in U.S. patent application Ser. No. 13/836,709,filed Mar. 15, 2013, entitled “Ceramic-Based Light Emitting Diode (LED)Devices, Components, and Methods,” and U.S. patent application Ser. No.13/836,940, filed Mar. 15, 2013, entitled “Ceramic-Based Light EmittingDiode (LED) Devices, Components, and Methods,” the entire disclosure ofeach of which are hereby incorporated by reference herein.

Further, in an embodiment, the two 40-die LED enclosures are replaced bya single 80-die or even 120-die LED or any other number of LED dies inan enclosure 73 similar or identical to (except as to size) theenclosure 46 mounted on the second circuit board 72.

An operating network or circuit discussed in detail hereinafter operatesthe LED dies in the enclosure 73 to cause the luminaire 20 to develop adesired distribution of light at a desired lumen output level. Each LEDdie may be a single white or other color LED (i.e., a single die,packaged in a housing or enclosure or unpackaged), or each may comprisemultiple LEDs either mounted separately or together. For example, atleast one phosphor-coated or phosphor-converted LED, such as ablue-shifted yellow LED, either alone or in combination with at leastone color LED, such as a green LED, a yellow LED, a red LED, etc. may beincluded. The number and configuration of LEDs may vary depending on avariety of factors.

Specifically, in those cases where a soft white illumination withimproved color rendering is to be produced, each LED die or a pluralityof such dies may comprise one or more blue shifted yellow LEDs and oneor more red LEDs. The LEDs may be disposed in different configurationsand/or layouts as desired. Different color temperatures and appearancescould be produced using other LED combinations, as is known in the art.In one embodiment, each die comprises a device as described in U.S.patent application Ser. No. 61/948,359, filed Mar. 5, 2014, entitled“Solid State Lighting Apparatuses, Systems, and Related Methods.” Inanother embodiment, a plurality of LEDs may include at least two LEDshaving different spectral emission characteristics. If desirable, one ormore side emitting LEDs disclosed in U.S. Pat. No. 8,541,795, filed Oct.10, 2005, entitled “Side-Emitting Optical Coupling Device,” the entiredisclosure of which is incorporated by reference herein, may be used. Insome embodiments, one or more LEDs may be disposed within a couplingcavity with an air gap being disposed between the LED and a light inputsurface. In any of the embodiments disclosed herein the LEDs preferablyhave a lambertian or near-lambertian light distribution, although eachmay have a directional emission distribution (e.g., a side emittingdistribution), as necessary or desirable. More generally, anylambertian, symmetric, wide angle, preferential-sided, or asymmetricbeam pattern LED(s) may be used.

Specifically, as seen in FIGS. 4 and 4A, the first board 70 includesthree power input terminals 74 a-74 c to which incoming hot, neutral,and ground connections, respectively, can be effectuated. Thus, ACutility power is directly provided to the luminaire 20. The ground powerterminal 74 c is electrically connected to a bore 76 (FIG. 4) surroundedby an electrically conductive material (e.g., copper). The first board70 is preferably secured and electrically connected to the housing 24(FIGS. 1 and 2), which itself may be electrically conductive, by asingle screw or other electrically conductive fastener 78 extendingthrough the bore 76. Preferably the single screw is the only device thatmounts the first board 70 in the housing 24. This arrangement eliminatesthe need for a separate wire to ground the conductive housing of thefixture.

Referring to the schematic diagram of FIG. 5, also disposed on the firstboard 70 in one embodiment is a fuse FI, a three-stage surge protectioncircuit comprising metal oxide varistor devices RV1-RV4, resistorsR1-R3, diodes D1-D4 connected in a full bridge rectifier configuration,and a rectifier diode D5 that functions as a protective device. Anambient light sensor 80 (visible in FIG. 1) is mounted in a receptacle81 (FIG. 2) on the housing 24 and is connected in series with the fuse F1. The ambient light sensor 80 acts as a switch. Specifically, when thelevel of ambient light drops below a predetermined threshold anelectrical path is established by the sensor 80 thereby delivering powerto the balance of the operating circuit and causing the luminaire 20 toilluminate.

If desired, a protective plastic cover 82 (FIGS. 2, 4, and 4A) may bedisposed over one or more components carried by the first board 70. Ifdesired, some or all of the components on the first board 70 may bepotted.

The three-stage surge protection circuit operates to clamp transientvoltages across the varistor RV3 to about 600 volts, and further clampstransient voltages across the varistor RV4 to about 300 volts. Thevoltage across the rectifier diode D5 is clamped to about 230 volts. Inaccordance with one exemplary embodiment of a voltage supplymethodology, a full-wave rectified unidirectional pulsating voltage orother waveform is developed and applied without filtering to the secondcircuit board 72, so that a switched mode power supply or other powerconverter and filtering components, such as electrolytic capacitors andinductors, are not needed. While this voltage results in some flickeringof LEDs because of turn-on and turn-off of same as noted in greaterdetail below, such flickering is sufficiently minimal so as not tooutweigh the benefits of reduced part count, cost, maintenance, andother benefits.

Further, in at least some prior luminaires, the voltage supplymethodology disclosed herein was considered unsuitable for use inapplications subject to voltage surges and other voltage variations,such as in outdoor lighting where such variations are commonlyexperienced. The three-stage voltage clamping afforded by the protectioncircuit renders the present voltage supply methodology suitable foroutdoor use, thereby providing a reliable and inexpensive outdoorluminaire.

The second circuit board 72 includes the LED enclosure 73 and at leastone driver circuit 84, and more preferably first, second, and third (ormore) driver circuits 84 a, 84 b, 84 c, respectively, that may beidentical to one another, and which are coupled together in parallel andsupply drive current to first, second, and third separate sets of LEDs87 a, 87 b, 87 c, respectively, disposed in the enclosure 73. Becausethe driver circuits 84 a-84 c are preferably identical to one another,only the driver circuit 84 a will be described in detail herein. An LEDdriver integrated circuit 85 preferably manufactured and sold by AltoranChips and Systems, Inc. of Santa Clara, Calif., under part numberACS1004 is utilized together with associated components R4-R8 and an LEDconnection pad 86. If desired, a sequential linear LED Drivermanufactured and sold by Supertex Inc. of Sunnyvale, Calif., under partnumber CL8801 could be used as the integrated circuit 85. The first setof LEDs 87 a is coupled to the connection pad 86. The LEDs 87 a arefurther subdivided into four subsets 87 a-1, 87 a-2, 87 a-3, and 87 a-4that are coupled via the connection pad 86 to a full wave rectifiedwaveform developed on a conductor 88 a, and conductors 88 b, 88 c, 88 d,and 88 e coupled to outputs L1-L4 of the integrated circuit 85 (themanufacturer of the IC 85 designates these outputs as LED1-LED4,respectively). It should be noted that each subset 87 a-1 through 87 a-4may include the same or different numbers of LEDs. As seen in FIG. 5A,the subsets 87 a-1 through 87 a-4 are sequentially turned on and offduring each cycle of the full wave rectified waveform developed by thefull wave rectifier comprising the diodes D1-D4. Specifically, the firstLED subset 87 a-1 is on during a period tD1 comprising the full periodof the full wave rectified waveform except those portions where theapplied rectified voltage is less than the forward turn on voltage forthe subset 87 a-1 at the beginning and end of each period. The secondLED subset 87 a-2 is on together with the first LED subset 87 a-1 duringa shorter interval tD2 of each waveform period when the appliedrectified voltage less the voltage drop across the first LED subset 87a-1 exceeds the forward turn on voltage of the second LED subset 87 a-2.The third LED subset 87 a-3 is on together with the first and second LEDsubsets 87 a-1, 87 a-2 during a yet shorter interval tD3 of eachwaveform period when the applied rectified voltage less the voltage dropacross the first and second LED subsets 87 a-1, 87 a-2 exceeds theforward turn on voltage of the third LED subset 87 a-3. Further, thefourth LED subset 87 a-4 is on together with the first through third LEDsubsets 87 a-1 through 87 a-3 during a still shorter interval tD4 ofeach waveform period when the applied rectified voltage less the voltagedrop across the first through third LED subsets 87 a-1 through 87 a-3exceeds the forward turn on voltage of the fourth LED subset 87 a-4.This switching is facilitated by the IC 85 via the outputs L1-L4, whichshort out or otherwise remove drive from those LED subsets when theapplied voltage is insufficient to properly energize the LEDs of suchsubset. As should be evident from the foregoing, one can change thenumber of individual dies inside one or more of the LEDs and/or changethe number of LEDs in each subset to alter the voltage threshold atwhich different banks of LEDs will turn on, so that efficiency can beoptimized.

If desired, one could reduce flickering by biasing the full waverectified voltage onto a positive DC level (i.e., shifting the waveformin the positive direction) or otherwise modifying the applied waveformto prevent cyclic full or partial turn-off of some or all of the LEDs87.

Significantly, the second circuit board 72 is substantially smaller thanthe combined sizes of the circuit boards of the lighting modules 40, 42,and, in fact, the second circuit board 72 may be no larger, or slightlylarger or smaller than the circuit board 44 alone. By rearranging thecomponents onto a low-cost circuit board having non-heat producingcomponents and placing heat producing components on a heat dissipatingboard, and further increasing the number of LED dies in the LEDenclosure 73, one can reduce material costs and obtain the same or evenincreased lumen output. This is because duplicative components areeliminated and the two relatively expensive heat dissipating circuitboards of the modules 40, 42 are replaced by an inexpensive circuitboard 70 made of, for example, FR-4 material and a single heatdissipating circuit board 72 of approximately the same size as one ofthe heat dissipating boards 44.

Referring to FIGS. 2 and 4, the modules 40, 42 shown in FIG. 3 arereplaced in the housing 24 by the circuit boards 70, 72 shown in FIG. 4.In the embodiment shown in FIG. 2, the circuit board 72 may be centrallylocated on a planar surface 90 (the base 47 is not needed and may beomitted) and retained thereon by any suitable means, such as a retainerclip 91 and fasteners 92 and/or an adhesive, whereas the circuit board70 may be disposed in a compartment 92 of the housing 24 remote from thecircuit board 72 and secured therein by any suitable means. Thetransparent optical member 26 is sealed to the housing 24 covering thecircuit board 72 and is retained thereon by an adhesive and/or othermeans. The housing 24, optical member 26, and associated components ofthe luminaire 20 are described in greater detail in U.S. patentapplication Ser. No. 14/618,884, entitled “LED Luminaire and ComponentsTherefor,” the entire disclosure of which is hereby incorporated byreference herein.

The luminaire 20 is capable of producing different light distributionsdepending upon the choice of optical member 26. Different opticalmembers 26 have different shapes to effectuate different illuminationdistributions. For example, one embodiment of the optical member 26 maybe shaped to direct light outwardly and away from an area directly belowthe optical member 26 to produce an illumination distribution thatincludes a first extent along an x-axis and a second extent along ay-axis perpendicular to the x-axis, wherein the first extent and thesecond extent are symmetric x-axis and y-axis, respectively. A furtherembodiment of the optical member 26 may be shaped to produce a furtherillumination distribution that includes a first extent along an x-axisand a second extent longer than the first extent along a y-axisperpendicular to the x-axis.

The luminaire disclosed herein is particularly adapted for use inoutdoor or indoor general illumination products (e.g., streetlights,high-bay lights, canopy lights, parking lot or parking structurelighting, yard or other property lighting, rural lighting, walkwaylighting, warehouse, store, arena or other public building lighting, orthe like). According to one aspect the luminaire disclosed herein isadapted for use in products requiring a total lumen output of betweenabout 1,000 and about 12,000 lumens or higher, and, more preferably,between about 4,000 and about 10,000 lumens and possibly higher, and,most preferably, between about 4,000 and about 8,000 lumens. Accordingto another aspect, the luminaire develops at least about 2000 lumens.Further, efficacies between about 75 and about 140 lumens per watt, andmore preferably between about 80 and about 125 lumens per watt, and mostpreferably between about 90 and about 120 lumens per watt can beachieved. Still further, the luminaires disclosed herein preferably havea color temperature of between about 2500 degrees Kelvin and about 6200degrees Kelvin, and more preferably between about 2500 degrees Kelvinand about 5000 degrees Kelvin, and most preferably between about 3500degrees Kelvin and about 4500 degrees Kelvin. Further, the opticalefficiency preferably may range from about 70% to about 95%, mostpreferably from about 80% to about 90%. A color rendition index (CRI) ofbetween about 70 and about 80 is preferably attained by the luminairedisclosed herein, with a CRI of at least about 70 being more preferable.Any desired particular output light distribution, such as a butterflylight distribution, could be achieved, including up and down lightdistributions or up only or down only distributions, etc.

Referring to FIG. 6, an optional adapter circuit 100 mounted on acircuit board 101 (shown schematically by dashed lines) may be providedto allow a utilization circuit such as the luminaire 20 to be powered bydifferent electrical supply voltages or other electrical parameter(s).The adapter circuit 100 may be coupled to the components on the circuitboard 72. The adapter circuit 100 may receive power from a circuit 102that operates in a fashion similar or identical to the circuit of FIG. 5including the sensor 80, a fuse F2, varistors RV5-RV8, resistors R9-R11,diodes D7-D10 connected in a full-wave rectification configuration, anda rectifier diode D11. In the illustrated embodiment, the adaptercircuit 100 comprises electrical components, such as jumpers 106, 107,and 108, connectable between input terminals T1 and T2 coupled to therectifier diode DII and output or connection terminals J1-J4.Specifically, the rectifier diode D7-10 is coupled across the connectionterminals J4 and J3, the jumper 106 is selectively coupled across theconnection terminals J4 and J1, the jumper 107 is selectively coupledacross the connection terminals J1 and J2, and the jumper 108 isselectively coupled across the connection terminals J2 and J3. When afirst magnitude of an electrical input power parameter is to be providedto the luminaire 20, such as an input voltage of 120 volts RMS AC, thejumpers 106 and 108 are provided and connected as shown in FIG. 6, whilethe jumper 107 is omitted and no component is populated at the locationfor the jumper 107 on the circuit board 101 (even though the jumper 107is shown in FIG. 6 for the sake of explanation). Such a configurationresults in the terminals J1 and J4 being connected together and theterminals J2 and J3 being connected together. The result is that thefull wave rectified voltage is developed between connection terminals J1and J2 as well as the connection terminals J3 and J4 of the adaptercircuit 100. Driver circuits 110 and 112 identical or similar to ordifferent than the driver circuits 84 a-84 c are coupled to theterminals J1, J2 and to the terminals J3, J4, respectively, so that eachdriver circuit 110, 112 receives the full wave rectified power.Conversely, as seen in FIG. 6A, when a second magnitude of an electricalinput power parameter is to be provided to the luminaire 20, such as aninput voltage of 240 volts RMS AC, the jumpers 106, 108 are omitted andno components are populated at the locations provided therefor on thecircuit board 101, while the jumper 107 is coupled between theconnection terminals J1 and J2. Further, the driver circuit 110 iscoupled to the terminals J1 and J4 and the driver circuit 112 is coupledto the terminals J2 and J3. The driver circuits 110 and 112 are therebycoupled in series across the full wave rectification bridge comprisingthe diodes D7-D10. The LEDs operated by the driver circuits 110, 112present a nearly resistive load to the full wave rectified voltagedeveloped across the terminals J4 and J3. The result is that the 240volt RMS full wave rectified waveform is shared equally between the LEDsoperated by the driver circuits 110 and 112, and hence, a drop ofone-half the full wave rectified voltage occurs between the connectionterminals J4 and J1 (due to the presence of the full wave rectifiedvoltage referenced to ground at the connection terminal J4 and one-halfof this voltage referenced to ground at the connection terminal J1) anda further drop of the remainder of this voltage occurs between theconnection terminals J2 and J3 (due to the presence of one-half the fullwave rectified voltage referenced to ground at the connection terminalJ2 and zero volts referenced to ground at the connection terminal J3).Thus, the LEDs operated by the driver circuits 110, 112 are operated atthe proper voltages in the manner described above in connection withFIG. 5.

As should be evident, the circuits of FIG. 5 or 6 may be used with anumber of parallel-connected driver circuits and LED subsets. Thecircuits of FIG. 5 or 6 could further be used to supply power to anumber of series-connected driver circuits and associated LED subsets.The ability to selectively use the circuits of FIG. 5 or 6 withparallel- or series-connected driver circuits and associated LED subsetsis facilitated by the adapter circuit 100. For example, 2, 4, 6, etc.parallel-connected driver circuits and associated LED subsets couldreceive power from a power source via the adapter circuit 100.Alternatively, the adapter circuit 100 could be modified to interconnectmore than two driver circuits and associated LED subsets in series,parallel, or combinations of series and parallel configurations. Forexample, as is readily apparent, one could modify the adapter circuit100 to include additional jumpers and connection terminals to permitthree driver circuits and associated LEDs subsets to be connectedtogether in series. This could be useful where higher supply voltagesare standard, as in Canada, which uses a 300 volt RMS AC standard. Insuch a case each LED subset experiences a nearly identical orsubstantially equal voltage drop thereacross.

As should also be evident, the adapter circuit 100 permits anassembler/installer to determine a magnitude of electrical power to besupplied to the luminaire and configure the circuit 100 based upon suchdetermination in a simple and convenient fashion. As should also beevident, one or more resistors or other electrical components may beprovided to appropriately modify the voltage (or other parameter ofelectrical power) delivered to the driver circuits, for example, by thefull bridge rectifier comprising the diodes D7-D10 and the rectifierdiode D11. It may also be noted that some or all of the jumpers 106-108may, at time of initial assembly, be secured to the circuit board 70 andmay comprise easily breakable (i.e., frangible) connections so that theadapter circuit 100 can be readily configured as necessary by breakingand removing selected jumpers from the circuit 100. Any or all of thejumpers 106-108 may be replaced by different electrical component(s)that can be selectively connected or disconnected from the circuit, orthat selectively connect or disconnect another component from thecircuit, such as resistors or other impedance devices, switches of anykind (manual or controlled), semiconductor or other devices, or thelike.

Any of the embodiments disclosed herein may include a power circuithaving a buck regulator, a boost regulator, a buck-boost regulator, aSEPIC power supply, or the like, and may comprise a driver circuit asdisclosed in U.S. patent application Ser. No. 14/291,829, filed May 30,2014, entitled “High Efficiency Driver Circuit with Fast Response” by Huet al. or U.S. patent application Ser. No. 14/292,001, filed May 30,2014, entitled “SEPIC Driver Circuit with Low Input Current Ripple” byHu et al., the entirety of both being incorporated by reference herein.The circuit may further be used with light control circuitry thatcontrols color temperature of any of the embodiments disclosed herein inaccordance with viewer input such as disclosed in U.S. patentapplication Ser. No. 14/292,286, filed May 30, 2014, entitled “LightingFixture Providing Variable CCT” by Pope et al., the entirety of which isincorporated by reference herein.

Further, any of the embodiments disclosed herein may be used in aluminaire having one or more communication components forming a part ofthe light control circuitry, such as an RF antenna that senses RFenergy. The communication components may be included, for example, toallow the luminaire to communicate with other luminaires and/or with anexternal wireless controller, such as disclosed in U.S. patentapplication Ser. No. 13/782,040, filed Mar. 1, 2013, entitled “LightingFixture for Distributed Control” or U.S. Provisional Application No.61/932,058, filed Jan. 27, 2014, entitled “Enhanced Network Lighting,”the entirety of both disclosures being incorporated by reference herein.More generally, the control circuitry includes at least one of a networkcomponent, an RF component, a control component, and a sensor. Thesensor, which may comprise the sensor 80 or any other sensor, mayprovide an indication of ambient lighting levels thereto and/oroccupancy within the room or illuminated area. Such sensor may beintegrated into the light control circuitry.

In summary, the present operating circuit is low in cost and yet iscapable of delivering equivalent or even increased lumen output, ascompared to previous operating circuits. The optional adapter circuitpermits the operating circuit to be configured for different electricalpower parameter input magnitudes, such as input voltage, in a simple andefficient manner.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar references inthe context of describing the invention (especially in the context ofthe following claims) are to be construed to cover both the singular andthe plural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the disclosure and does not pose alimitation on the scope of the disclosure unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the disclosure.

Numerous modifications to the present disclosure will be apparent tothose skilled in the art in view of the foregoing description. It shouldbe understood that the illustrated embodiments are exemplary only, andshould not be taken as limiting the scope of the disclosure.

What is claimed is:
 1. A lighting device comprising: rectificationcircuitry configured to produce rectified alternating current (AC) frominput AC comprising a plurality of cycles; lighting circuitry coupled tothe rectification circuitry, wherein the lighting circuitry comprisesfirst, second, and third sets of LEDs; wherein the sets of LEDs areconfigured to turn on in sequence at least twice per cycle to togetherdevelop an output level of at least about 2000 lumens.
 2. The lightingdevice of claim 1, further comprising driver circuitry coupled to therectification circuitry and the lighting circuitry.
 3. The lightingdevice of claim 2, wherein the driver circuitry comprises first andsecond driver circuits.
 4. The lighting device of claim 3, wherein thefirst and second driver circuits are coupled together in series.
 5. Thelighting device of claim 3, wherein the first and second driver circuitsare coupled together in parallel.
 6. The lighting device of claim 3,wherein an adapter circuit interconnects the first and second drivercircuits.
 7. The lighting device of claim 6, wherein the adapter circuitcomprises a plurality of jumpers.
 8. The lighting device of claim 3,wherein the driver circuitry further comprises third driver circuits. 9.The lighting device of claim 8, wherein the first, second, and thirddriver circuits are coupled together in parallel.
 10. The lightingdevice of claim 1, wherein each of the sets of LEDs is configured to beon for a different amount of time per cycle relative to each of theother sets of LEDs.
 11. The lighting device of claim 1, furthercomprising a housing configured to permit the lighting device to bemounted on an outdoor structure.
 12. The lighting device of claim 1,further comprising input circuitry coupled to the rectificationcircuitry, wherein the input circuitry is configured to provide theinput AC to the rectification circuitry.
 13. The lighting device ofclaim 1, wherein the lighting device is comprised in a streetlight, aparking structure light, a parking lot light, or an outdoor ruralluminaire.
 14. The lighting device of claim 1, wherein the first,second, and third sets of LEDs are each further configured to be on ateach voltage peak of the rectified AC.
 15. The lighting device of claim1, wherein the first, second, and third sets of LEDs are each furtherconfigured to be off when voltage of the rectified AC is below a turn onthreshold of at least one of the sets of LEDs.
 16. The lighting deviceof claim 1, wherein the sets of LEDs are further configured to turn offin sequence at least twice per cycle.
 17. A method of producing light,implemented by a lighting device, the method comprising: producingrectified alternating current (AC) from input AC comprising a pluralityof cycles; turning on first, second, and third sets of LEDs in sequenceat least twice per cycle to together develop an output level of at leastabout 2000 lumens.
 18. The method of claim 17, further comprisingcontrolling the sets of LEDs such that each set is on for a differentamount of time per cycle relative to each of the other sets of LEDs. 19.The method of claim 17, further comprising controlling the sets of LEDssuch that each of the sets of LEDs is on at each voltage peak of therectified AC.
 20. The method of claim 17, further comprising turning thesets of LEDs off in sequence at least twice per cycle.